Passing of blood in the stool occasionally, is considered quite normal for dogs. However, when there is a heavy discharge of red, or fresh clots of blood in the dog's stool, it can be a serious cause of concern. However, as a responsible pet owner, it is necessary that you have the possible causes investigated to winnow out the serious triggers.

Associated Medical Terms

In medical terms, the condition is known as hematochezia, or melena. In hematochezia, the blood in the dog's stool is fresh, bright red in color, and is most likely driven from the lower intestines -- typically, the colon and rectum. A dog suffering from hematochezia may also have a problem while defecating. The presence of hematochezia can be a sign of either a minor problem, or a potentially more severe disorder.

Melena causes the feces to look black, smelly, and tarry, indicating that the blood is digested and driven from the upper intestinal tract. However, normally, melena in dogs is more distressful and serious than an occasional case of hematochezia.
Causes

Generally, blood in the stool is a significant sign that points towards some kind of gastrointestinal disorder. A rare presence of blood can be considered as a minor or transient event. However, repeated occurrences along with diarrhea are more serious, which should not be ignored. Apart from gastrointestinal disorders, there are various other probable causes for the presence of blood and mucus in the stool, which are:
  • Bacterial infections, like food poisoning and typhoid
  • Dog allergies from food additives, emulsifiers, fats, or due to certain medications
  • Consumption of rat poison, or rats that have been poisoned
  • Intestinal parasites, or dog worms, including whipworm, tapeworm, and ringworm
  • Presence of benign and malignant tumors in the abdomen, or anal region
  • Disruption of colon, or rectum, due to fractures in the pelvic region
  • Ingestion of sharp things, like bone, sticks, plastic, or needles
  • Overeating, or abrupt changes in the dietary plan
  • Viral infections, like parvovirus and coronavirus
  • Blood clotting disorders (coagulopathy)
  • Inflammation of the colon, anal sacs, and rectum
  • Rectal cancer
  • Intussusception, i.e., telescoping of one part of the bowel into another

Diagnosis

The most common way of diagnosing this problem is by taking a stool sample to the veterinarian for detecting parasites, bacteria, or viruses that might otherwise not be visible to the naked eye.

Monitor and keep an eye on your dog's gums; they should be healthy pink and not whitish-gray, or yellow. Consult a vet as soon as possible if you notice a change in the gum appearance, as these are signs that indicate a loss of high amount of blood.

Your pet has to undergo a thorough physical examination to determine if it has been infected by any kind of anal sac infection, or not. Hence, the vet may conduct a blood test and/or an X-ray examination to check if your dog has swallowed any odd items.
Treatment

The treatment depends on the severity of the condition and its underlying cause. Antibiotics with anti-inflammatory and antibacterial properties, like dewormers can be given orally, or injected into the pet's body.

Consult a vet and get a fecal check done if you suspect the presence of worms. In fact, dogs should be checked for worms at regular time intervals even if they appear healthy. Routine worming can forbid whipworms, tapeworms, and roundworms.

Cleansing enema, or local surgeries may be employed to extract foreign bodies, like bones, sticks, and needles.

The dog may have to undergo a surgery to remove masses of colon, or rectum, if diagnosed with abnormal growth (cancer) in either region.

In severe cases, your dog may also suffer vomiting, lack of energy, loss of appetite, pale whitish-gray gums, and diarrhea. Here is when intravenous fluid and electrolyte treatments come into picture.

If the vet suggests making changes to your dog's diet, then new foods should be introduced, gradually. A sudden diet alteration could lead to vomiting, diarrhea, irritated bowels, and may be accompanied by feces covered in blood.

Do not feed human food to dogs; keep them away from it. Gastrointestinal disorders can be cured by feeding the dog a high-fiber, or hypoallergenic diet with water -- or substitute water with ice cubes -- to help relieve your dog from dehydration.

Let your dog go without food or treats for 12-24 hours, and in case of puppies, fasting should be not more than 12 hours. Post the 12-24 hour fast, a diet consisting of white rice, cottage cheese, 1 tbsp. of yogurt (for a medium-sized dog), boneless chicken, and boiled potatoes has proven to be helpful in curing or limiting blood in the stool. In fact, adding 2-3 cloves of garlic to your dog's dinner on a daily basis will also be beneficial.
Although the aforementioned remedies help to overcome the problem, they should only be given under the veterinarian's supervision to avoid any further complications and help promote your dog's optimal health.

Disclaimer: This article is for informative purposes only and does not in any way attempt to replace the advice offered by a veterinarian on the subject.